-TODO: -early go documentation suggested using a channel as a semaphore like this: (previous example). -the go memory model has been updated to make explicit that this idiom is allowed. (new example). -the previous example is also correct, just requiring needless func init work. -(CL 75130045) +The Go 1.3 memory model adds a new rule +concerning sending and receiving on buffered channels, +to make explicit that a buffered channel can be used as a simple +semaphore, using a send into the +channel to acquire and a receive from the channel to release. +This is not a language change, just a clarification about an expected property of communication.